Expression profiling of muscles from Fukuyama-type congenital muscular dystrophy and laminin-alpha 2 deficient congenital muscular dystrophy; is congenital muscular dystrophy a primary fibrotic disease?

Fukuyama-type congenital muscular dystrophy (FCMD) and laminin-alpha2 deficient congenital muscular dystrophy (MDC1A) are congenital muscular dystrophies (CMDs) and they both are categorized into the same clinical entity of muscular dystrophy as Duchenne muscular dystrophy (DMD). All three disorders share a common etiologic defect in the dystrophin-glycoprotein complex, which connects muscle structural proteins with the extracellular basement membrane. To investigate the pathophysiology of these CMDs, we generated microarray gene expression profiles of skeletal muscle from patients in various clinical stages. Despite diverse pathological changes, the correlation coefficient of overall gene expression among these samples was considerably high. We performed a multi-dimensional statistical analysis, the Distillation, to extract determinant genes that distinguish CMD muscle from normal controls. Up-regulated genes were primarily extracellular matrix (ECM) components, whereas down-regulated genes included structural components of mature muscle. These observations reflect active interstitial fibrosis with less active regeneration of muscle cell components in the CMDs, characteristics that are clearly distinct from those of DMD. Although the severity of fibrosis varied among the specimens tested, ECM gene expression was consistently high without substantial changes through the clinical course. Further, in situ hybridization showed more prominent ECM gene expression on muscle cells than on interstitial tissue cells, suggesting that ECM components are induced by regeneration process rather than by 'dystrophy.' These data imply that the etiology of FCMD and MDC1A differs from that of the chronic phase of classical muscular dystrophy, and the major pathophysiologic change in CMDs might instead result from primary active fibrosis.     

Induction of Freeze-sensitive Mutants from a Freeze-tolerant Yeast,Torulaspora delbrueckii

Freeze-sensitive strains of yeast were induced from a freeze-tolerant yeast Torulaspora delbrueckii by incubation with ethyl-methane sulfonate as a mutagen. A maximum ratio of mutation was attained by the incubation at 30°C for 75min. One-hundred and fifty strains of freeze-sensitive yeast were selected by plating-culture for the first screening. The freeze-tolerance ratio of each strain was examined based on the fermentative activity before and after freezing in liquid medium and dough. Strain 60B3 showed the highest freeze-sensitivity in a pre-fermented frozen dough (pre-fermented at 30°C for 2h, and frozen at ?20°C for 7 days) among eight strains finally selected.     

Familial resemblances in blood leukocyte DNA methylation levels

Epigenetic factors such as DNA methylation are DNA alterations affecting gene expression that can convey environmental information through generations. Only a few studies have demonstrated epigenetic inheritance in humans. Our objective is to quantify genetic and common environmental determinants of familial resemblances in DNA methylation levels, using a family based sample. DNA methylation was measured in 48 French Canadians from 16 families as part of the GENERATION Study. We used the Illumina HumanMethylation450 BeadChip array to measure DNA methylation levels in blood leukocytes on 485,577 CpG sites. Heritability was assessed using the variance components method implemented in the QTDT software, which partitions the variance into polygenic (G), common environmental (C), and non-shared environmental (E) effects. We computed maximal heritability, genetic heritability, and common environmental effect for all probes (12.7%, 8.2%, and 4.5%, respectively) and for statistically significant probes (81.8%, 26.9%, and 54.9%, respectively). Higher maximal heritability was observed in the Major Histocompatibility Complex region on chromosome 6. In conclusion, familial resemblances in DNA methylation levels are mainly attributable to genetic factors when considering the average across the genome, but common environmental effect plays an important role when considering statistically significant probes. Further epigenome-wide studies on larger samples combined with genome-wide genotyping studies are needed to better understand the underlying mechanisms of DNA methylation heritability.     

生物合成3-羟基丙酸的代谢工程研究进展

3-羟基丙酸(3-HP)作为一种重要的平台化合物,以此为底物能够合成多种具有商业潜质的生物制品。野生菌合成3-HP产量较低,严重限制3-HP的大规模应用与生产,通过改造合成代谢通路的相关基因,构建以廉价底物为碳源的工程菌株,实现降低生产成本提高产量的目的。文中将对近年来国内外通过代谢工程合成3-羟基丙酸的研究进展进行概述,并对甘油途径、丙二酸单酰辅酶A途径、β-丙氨酸等途径合成3-HP的优缺点进行总结分析,对3-HP未来发展前景进行展望。     

代谢网络定量分析研究进展

综述了代谢工程中代谢控制分析、代谢通量分析、生化系统理论、途径分析、控制论模型等定量分析方法的基本理论,以实例说明了这些方法的应用,并对代谢分析方法的发展进行了展望。     

真菌发光途径的研究与应用进展

真菌发光途径(fungal bioluminescence pathway, FBP)是一种来源于真菌的生物发光代谢途径。其能够利用FBP途径基因簇表达的蛋白,以咖啡酸为底物,合成真菌荧光素,在真菌荧光素酶的催化下,生成不稳定高能小分子,之后分子能量衰减释放出波长约为520 nm的绿色荧光。在发光真菌中,真菌发光途径基因在进化上非常保守。与其他生物发光系统不同的是,真菌发光途径适合于真核生物,特别是植物中的工程化应用。目前,经过代谢路径优化的发光植物可以持续发出肉眼可见光,照亮周围环境。该发光系统在生物检测、生物传感器、发光园艺植物培育和绿色照明等领域具有广阔的应用前景。     

生物法合成3-羟基丙酸的研究进展

从3-羟基丙酸的性质出发,介绍了生物法合成3-羟基丙酸以及它在生物体内的五种代谢途径,此外还简要介绍了3-羟基丙酸在合成生物聚酯、抗植物病虫害上的一些应用。     

Yeast genes involved in response to lactic acid and acetic acid: acidic conditions caused by the organic acids in Saccharomyces cerevisiae cultures induce expression of intracellular metal metabolism genes regulated by Aft1p

Using two types of genome-wide analysis to investigate yeast genes involved in response to lactic acid and acetic acid, we found that the acidic condition affects metal metabolism. The first type is an expression analysis using DNA microarrays to investigate 'acid shock response' as the first step to adapt to an acidic condition, and 'acid adaptation' by maintaining integrity in the acidic condition. The other is a functional screening using the nonessential genes deletion collection of Saccharomyces cerevisiae. The expression analysis showed that genes involved in stress response, such as YGP1, TPS1 and HSP150, were induced under the acid shock response. Genes such as FIT2, ARN1 and ARN2, involved in metal metabolism regulated by Aft1p, were induced under the acid adaptation. AFT1 was induced under acid shock response and under acid adaptation with lactic acid. Moreover, green fluorescent protein-fused Aft1p was localized to the nucleus in cells grown in media containing lactic acid, acetic acid, or hydrochloric acid. Both analyses suggested that the acidic condition affects cell wall architecture. The depletion of cell-wall components encoded by SED1, DSE2, CTS1, EGT2, SCW11, SUN4 and YNL300W and histone acetyltransferase complex proteins encoded by YID21, EAF3, EAF5, EAF6 and YAF9 increased resistance to lactic acid. Depletion of the cell-wall mannoprotein Sed1p provided resistance to lactic acid, although the expression of SED1 was induced by exposure to lactic acid. Depletion of vacuolar membrane H+-ATPase and high-osmolarity glycerol mitogen-activated protein kinase proteins caused acid sensitivity. Moreover, our quantitative PCR showed that expression of PDR12 increased under acid shock response with lactic acid and decreased under acid adaptation with hydrochloric acid.     

大肠杆菌细胞工厂的创建技术

大肠杆菌作为一种重要的模式工业微生物,在医药、化工、农业等方面具有广泛的应用.近30年来,多种代谢工程改造的新策略和新技术,被用于设计、构建和优化大肠杆菌化学品细胞工厂,极大地提高了生物法合成化学品的生产速率和产量.文中将从大肠杆菌途径设计、合成途径创建与优化和细胞全局优化三个方面,对大肠杆菌代谢改造起重要推动作用的技...     

Candida glycerinogenes不同碳源代谢的初步研究

研究了不同碳源对Candidaglycerinogenes的菌体生长、发酵液pH值及代谢产物的影响,结果发现以葡萄糖、果糖等单糖为碳源时茵体生长较快,最终生物量比以蔗糖、麦芽糖等二糖为碳源时高20％～30％;导致发酵前12h发酵液pH值明显下降的主要因素是乳酸;与葡萄糖为碳源转化为甘油相比,果糖为碳源时更易累积乙醇;以蔗糖、麦芽糖为碳源时,用于转化生成甘油的碳源明显降低,碳源主要用于茵体自身生物合成及HMP途径,以蔗糖为碳源时,用于乳酸、丙酸及柠檬酸生物合成的碳源较麦芽糖明显提高,TCA途径代谢较为活跃。     

遗传改造微生物代谢途径生产新型柴油燃料的研究进展

生物柴油是一种能替代柴油的可再生燃料,然而通过植物油料化学转酯化生产的第一代生物柴油在性能和生产工艺上有很多缺点。近年来随着合成生物学和代谢工程的迅速发展,通过选择合适的微生物并利用各种生物技术改造其代谢合成途径,如脂肪酸合成途径、异戊二烯合成途径,研究人员能利用微生物直接生产性能更加优越、品质更高的新型第二代生物柴油——长链烷烃。文章总结了目前遗传改造微生物代谢途径生产新型柴油的研究进展,并指出目前该领域存在的问题以及今后的发展方向。